1. Field of the Invention
The present invention relates to the field of adjustable row or transfer tools, and more particularly to a novel row tool having specially located relief slots and slits permitting adequate strength of the row tool while minimizing undesirable deflection of a surface intended to be made level during a lapping procedure.
2. Description of the Prior Art
Magnetic heads are used extensively in data processing systems, such as disk drives. During head production, batch fabrication is employed whereby a multiplicity of transducers are deposited in a row on a tool or bar composed of ceramic, steel or the like for lapping, polishing and processing simultaneously. The tool or bar serves as a support or substrate for the row of transducers and subsequently is divided into head slider elements. During the manufacture of magnetic heads or head sliders with thin film transducers, the pole tips at which the transducing gap is disposed are ground and lapped to achieve a desired throat height at which optimum data signal processing can be realized. The throat height of all the transducers made during a production run for use with a data storage product must be maintained within a defined limited tolerance.
A problem that exists during the lapping process is row bow, which is a condition wherein the ceramic bar is stressed and assumes an undesirable curvature. As a result, the transducer pole tips that encompass the transducing gap are differently aligned relative to the grinding or lapping plate and, therefore, are lapped at different rates. This condition results in different throat heights for the transducers disposed along the bar or row tool. Prior art adjustment techniques to compensate for row tool bow, balance and to minimize undesirable deflection of a surface to be made level are time-consuming, subject to operator error, cannot accurately correct for row bow and do not afford optimum production yield.
Prior attempts to correct for ceramic bar or slider bar distortion are disclosed in U.S. Pat. Nos. 5,117,589 and 5,203,119. However, problems have been encountered, which stem from the use of a mechanical plunger operable in response to sensed transducer signals to apply pressure to critical locations on the row tool carrying the slider bar. Movement of the plunger and transfer of the loads from the plunger to the row tool are notalways accurate enough to achieve desired bending moments in the row tool. Also, no provision is made in prior devices to adjust for balance or tilt of the row tool prior to the lapping procedure. Furthermore, the open cavities or slots in the body of prior transfer or row tools are so large and randomly placed on the tool that the strength of the tool is compromised resulting in material fatigue and early replacement.
Therefore, a long-standing need has existed to provide an adjustable row tool which includes precisely located stress relief openings without compromising strength or flexibility while being dynamically adjusted during a lapping or grinding procedure.